Here's my suggestion for an upgrade to the 3 northumbria depots (Fleet numbers are just suggestions:

Ashington:

15x Scania fencer F1s (4x for the 57/57A, 4x for the 35, 2x for the X14 & 4 spares) these will be numbered 4601-4614. All these will be new in the new arriva livery and 4601/02 will be branded for service X14 Newcastle-Morpeth-Rothbury-Thropton, 4603-4606 being branded for services 57/57A Cramlington-Seaton Deleval-Monkseaton-Whitley every 30 minutes & 4607-10 being branded for service 35 Morpeth-Ashington-Newbiggin-Woodhorn 4611-4614 will not have route branding as they will be spare, these will all feature USB charging, Leather Seats, NSAs & free WiFi.

20x Wright Streetdeck OM936s (4 for the X15, 4 for the X20, 6 for the X18 & 6 spare which means 2 spares for each route) these will be numbered 7701-7720, these will feature free WiFi, NSAs, USB charging, leather seats, tables & wireless charging with these all coming in sapphire livery with 7701-04 carrying branding for service X15 Newcastle-Morpeth-Alnwick-Berwick every hour to Alnwick & every 2 hours to Berwick, 7705-7708 will be branded for the X20 Newcastle-Ashington-Amble-Alnwick every 60 minutes, 7709-7714 will be branded for X18 explore the northumbria coast branding similar to the X93 with 7715-20 being spare and will have no route branding.

These changes will release all Ashington's medibus Fleet, 7510-17, 4653/55/64, 7445/46/84/86 up for withdrawal and 7529-33/53-56 up for cascade

Jesmond:

7529-33/53-56 to Jesmond for the 43/44/45 to release 7501-9 up for withdrawal

20x 10.8M damiler Streetlites for to replace the solos on the 46, 51, 51A, 55 & 553 all of these will carry the new livery with NSAs, Free Wi-Fi,  USBs & leather seats, these will not carry route branding. These will be numbered 1614-34

10x Wright Streetlite HEVs (8 for the 306 (I think thats the post 2021 PVR) & 2 spare)
These will carry the new arriva livery with 306 branding for the 306 Newcastle-Coast Road-Battle Hill-North Shields-Tynemouth every 15 minutes with the spares not being route branded, these will be numbered 1635-44 and will have the same features as tge 10.8M versions 

this will allow all jesmond's B7s, 57 & 58 reg E400s & solos to be withdrawn and will also allow the 306 branded pulsars to go on the 685 (with a little repaint) allowing 4660-62 to be withdrawn 

Blyth:

16x E200MMCs to replace the pulsars, darts and solos on expresses these will come in the new arriva livery  and will have the same features as all other single deckers mentioned. Unsure of Fleet numbers 

2x mellor stratas 1 for the 58 and one for a spare/switch over bus for the 58 these will be in the new livery and branded for the 58 East Hartford-Mannor Walks-High Pit-Hospital, these will feature Seat Belts, NSAs & Free WiFi. Unsure of Fleet numbers.

This leaves the darts and solos up for withdrawal & pulsars up for cascade